Page 1366 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

The foal 1341

VetBooks.ir Clinical presentation taken to measure the total and differential WBC
count and cortisol concentration, then 0.125 mg
Foals present with some or all of the following physical
characteristics (Fig. 14.7): small and underweight; slow
cularly and a blood sample taken 2 hours post injec-
to stand and suck; poor body condition; silky mole-like short-acting ACTH (synacthen) is given intramus-
coat; domed forehead; floppy ears and discoloured tion to evaluate changes in the total and differential
tongue; flexor tendon laxity and weak musculature; WBC count, and cortisol concentration. Mature
pale mucous membranes; weakness and occasionally foals show an increase in total WBC count and an
incoordination; and poor thermoregulation. increase in the neutrophil:lymphocyte ratio (>2:1).
Further investigations may reveal: incomplete Cortisol concentration should double in mature
ossification of cuboidal bones and joint instability foals. Radiographs of the lungs are helpful in order
(Fig. 14.8); poor tolerance to enteral feeding, with to assess the severity and type of respiratory abnor-
colic and abdominal distension; poor respiratory malities (e.g. atelectasis).
function with slow rate and/or abnormal respiratory
pattern; altered mentation; increased susceptibility Management
to infection; dehydration; leucopenia and neutrope- These foals require intensive and supportive treat-
nia; neutrophil:lymphocyte ratio <2:1; hypoxia and ment with an enormous input of nursing care
hypercapnoea; and acidosis. (Fig. 14.9). Owners of such foals need to be made
aware of this at the outset.
Differential diagnosis
Sepsis; perinatal asphyxia syndrome. Prenatal corticosteroids
In humans the use of pre-natal betamethasone has
Diagnosis been shown to hasten fetal maturation and improve
Diagnosis is based on the history of the pregnancy, outcome. The opportunity for steroid use in the
physical appearance, degree of ossification of the mare is limited and the most appropriate dose and
cuboidal bones and haematological parameters. drug have not been established. Large doses of dexa-
An adrenocorticotropic hormone (ACTH) stimu- methasone can be used in some mares to hasten the
lation test can be used. An initial blood sample is onset of parturition and fetal maturation.

14.7 14.8

Fig. 14.8
Dorsopalmar
radiograph of
incomplete
ossification of the
carpal bones of a
premature foal.
Note the rounded
outline of the
Fig. 14.7 A foal showing some of the classic signs osseous centres of
of dysmaturity including a domed forehead, low body the carpal bones
weight, silky coat and laxity of the limbs, especially in and the apparent
the carpal joints. It has a poor suck reflex and is being large space in
assisted onto the mammary gland of the mare. between them.